Mining in focus
An underground surveyor in action.
Nicolaas Steenkamp safety department’ s planning and preventative or proactive measures. The maps are crucial for proto-teams and mine rescue in the event of an incident rescue and / or recovery operation. Accurate maps are lifesavers when emergency ventilation or communication and supply boreholes need to be drilled.
Surface mine surveying
In surface operations, the mine survey data will determine the development of the open pit. The data is used by the rock engineers and geotechnical engineers to identify potential risks, such as slope failure, by monitoring slow movements or deformation as detected by the mine survey. The data is also used to determine the risk of encountering failures due to, for example, wedges being exposed by excavations. The mine survey data is also used to determine the rate of development of the open pit and the remaining resources and reserves, based on the pit-shell model. Whittle optimisation can be applied to increase or decrease the size of the pit-shell, using the survey data. Other surface survey tasks are related to surface layouts, which will include buildings and other permanent or temporary structures. Surface surveys are also used to measure stockpiles.
The maps generated for a surface mining operation are a representation
of the true size and shape of all excavations. The map should contain sufficient cross-sections showing the advances made in the operation and the areas reclaimed or again filled in.
3-D scanning surveys
The introduction of laser 3-D scan has revolutionised the mine surveying industry. Mine surveys can now be completed in a fraction of the time of a traditional survey by a suitably qualified surveyor. The laser 3-D scans can be viewed interactively and give a much richer texture and level of detail. The 3-D model has the option of a‘ fly-through’ view and offers detail as small as nuts and bolts. Incident investigations will also benefit greatly from this advance in surveying, offering 3-D views that can be used by the incident investigation team, without the risk of disturbing the scene or placing more people at risk by entering the danger area. The data can also be used to reconstruct the event or to run simulations.
Laser survey scanners are able to capture large amounts of data in a point cloud. This data is then used to create a CAD model. The latest technology can capture a large number of points( approximately 976 000 per second), accurately and quickly. Buildings, industrial plants, and mine voids can be scanned and models constructed of the‘ as built’ conditions.
Drones
The increasing commercial availability of drone or unmanned aerial vehicles( UAV) has also had a major impact on the mine surveying industry. Drone-based data collection aids in increasing productivity by reducing the amount of time needed to conduct a survey and minimising the amount of time required to mobilise from one survey position to the next. It also reduces the reliance on images collected by third parties and is significantly cheaper than conventional aerial photography from an aeroplane or helicopter.
Surveyors are able to collect accurate spatial data from the air using a drone or UAV technology and can vastly reduce risk by minimising the time staff spend on site. The drones can also be used to survey risky areas within active open pits or dangerous slopes. The main limitation in South Africa on the use of UAVs or drones is that pilot licences are required to operate it legally.
Work is also being done to effectively use drones in underground operations. In parallel, work is being done to develop automated or semi-autonomous vehicles to conduct surveys. Both technologies will reduce the risk, especially in dangerous areas. b
[ 26 ] MINING MIRROR APRIL 2018